When one intends to grow natural turfs, grasses or flowers at a ground such as a general house garden, a bank of a river, a park or a golf course, or a planting zone of a building, road or the like, he or she directly sows plant seeds in the ground or planting zone, or plants young plants therein. An appropriate anti-flow-out fence or the like may be provided for preventing flow-out of the sowed seeds or planted young plants as well as applied fertilizer by rain, wind and irrigated water.
In the sport facilities, fields of soil or natural turfs have been used for a long time. However, a difficult or laborious work is required for maintaining such fields, so that artificial turfs are now used in many cases.
However, the artificial turf is not suitable to some kinds of sports such as a soccer, so that such sports are played on the natural turf even in these days.
In the sport facilities, however, the field in which the natural turf is directly planted in the ground suffers from such problems that it is difficult to control the growth of the turf, and that a long time is required for repairing a turf damaged by the play, which may disable continuous use thereof. In view of this, such a method may be used that natural turfs which have been grown at another place are laid on a leveled and prepared base ground, and a possible damaged portion can be replaced with a new turf.
Natural turfs which have been grown at a different place and are cut into an appropriate size are used for laying them in the sport facilities and for replacing a damaged turf portion with it, as is well known. In connection with this, one can envisage a semi-artificial natural turf sheet structure which does not use natural soil and can be transferred.
Such a turf sheet structure may be used at grounds such as a general house garden, a bank of a river, a park, a golf course, a hillock and a seaside as well as planting zones of various buildings, roads or the like.
As an example of a semi-artificial natural turf sheet structure, Japanese Laid-Open Patent publication No. 51-119108 (1976) has disclosed a turf mat which can be rolled up and includes a turf growing soil layer made of saw-dust, an underlying mesh mat and a water-proof base sheet in a layered fashion. Also, Japanese Laid-Open Patent publication No. 54-117732 (1979) has disclosed a turf sheet in which soil or sand is laid on a net, and a turf is grown on the same. Japanese Laid-Open Patent publication No. 60-95004 (1985) has disclosed a structure, in which a rubber mat or a synthetic resin plate provided with holes are laid in a place for growing a natural turf, and the holes are filled with soil, sand, turf runners, fertilizer and water retaining material for growing the turf. Japanese Laid-Open Patent publication No. 62-25907 (1987) has disclosed a mat which is mainly made of a rock wool holding turf seeds mixed thereinto. Japanese Laid-Open Patent publication No. 63-91015 (1988) has disclosed a planting mat, in which a rock wool is integrally provided with a frame member having substantially equally spaced tip ends and a bottom in a matrix form, and turf seeds are contained in the rock wool. Japanese Laid-Open Patent publication No. 2-104216 (1990) has disclosed a long-sheet product in a roll form, in which turfs are decomposed and expanded into elongated forms, stripe-shaped runners are arranged on a net having an appropriate mesh size, and their top surfaces are covered with a water-soluble paper sheet. Japanese Laid-Open Patent publication No. 3-247204 (1991) has disclosed the following natural turf base. A turf growing base member is made of a mixture of fertilizer and an inorganic light-weight soil member. Side and lower surfaces of the base member are covered with a lower sheet. An upper sheet is arranged on an upper surface of the base member. A member holding turf seeds are arranged at the lower surface of the upper sheet. A wave-shaped net is arranged between the turf seed holding member and the lower sheet and in the base member. The upper and lower sheets are integrally joined together by sewing threads, staples or the like.
However, when one intends to grow natural turfs, grasses or flowers at a ground such as a general house garden, a bank of a river, a park, a golf course, a hillock washed with rainwater, or a seaside exposed to a strong wind, or at a planting zone of a building, road or the like by directly sowing plant seeds in the ground or planting zone, or planting young plants therein, such a problem arises that the sowed seeds or planted young plants as well as applied fertilizer and others are liable to be flown out by rainwater, wind, irrigated water and others. Although the above problem can be prevented by provision of an anti-flow-out fence, or the like, this requires a laborious and time-consuming work.
Each of the natural turf sheet structures disclosed in the foregoing publications can be used without cutting it or after cutting it into an appropriate size. Further, it may be cut into an appropriate size after germination of turf seeds or growth, if necessary. Thereby, it can be laid over grounds such as a general house garden, a bank of a river, a park and a golf course as well as a place such as a planting zone of a building or a road, in which case the foregoing problems caused by direct sowing in the soil can be prevented to a certain extent. Also, the above structures can be used in sport facilities. However, the following problem arises.
The perforated rubber mat and synthetic resin plate disclosed in Japanese Laid-Open Patent publication No. 60-95004 are used not for entirely growing the turf but for intermittently growing the turf. Therefore, this cannot be employed when the turf is to be grown on a whole surface without a space. Particularly, this cannot be employed in sport facilities.
Further, except for the natural turf base, which includes the upper and lower sheets fixed together by the sewing threads, staples or the like as disclosed in Japanese Laid-Open Patent publication No. 3-247204, the structures disclosed in the foregoing publications cannot be used for the places such as sport facilities in which a severe force is applied thereto, because these structures are liable to be entirely decomposed and/or damaged. If the turf is damaged, e.g., by being shaved, an underlying material is exposed to exhibit an unpreferable appearance.
Even in the natural turf base disclosed in Japanese Laid-Open Patent publication No. 3-247204, if the turf is damaged, e.g., by being shaved, an underlying material is exposed, which similarly results in an unpreferable appearance.
Further, any of the natural turf sheet structures disclosed in the foregoing publications suffers from a problem that its weight is small and/or it cannot be sufficiently fitted with the underlying soil or the like, resulting in a poor stability. Therefore, a problem arises when it is laid, for example, over an inclined surface of a river bank, hillock or the like. Particularly, it is not suitable to the sport facilities, because players cannot stably play on the structure.
Description has been given on the case where the plants such as a turf are grown in grounds such as a general house garden, a bank of a river, a park and a golf course as well as planting zones of various buildings, roads or the like, fields of various sport facilities and others. In addition to these places, it is preferable to plant the natural turf at concrete walls of concrete constructions such as a concrete dam in some cases in order to protect the construction and/or improve an appearance.
Generally, dams are used for irrigation and water control, and more specifically, for storing water for electric power generation, irrigation, public water, industrial water or the like, and/or for preventing flood or controlling a water level. As a kind of dam, there has been a concrete dam constructed from concrete.
Generally, outer surfaces or walls of the concrete dam are not finished or coated. However, the unfinished concrete surface is directly exposed to the sunshine, wind and rain, so that they are liable to be deteriorated. In order to prevent the deterioration, outer finishing may be effected on the concrete surface as is done in ordinary buildings. However, the concrete dam, which is a huge construction, requires a vast sum of money for finishing its outer surfaces, so that the outer surfaces are not actually finished.
Some of huge dams are tourist attractions, in which case unfinished concrete surfaces of the dams present an unpreferable scene and sense of incompatibility with respect to surrounding green.
As measures for the above, it may be envisaged to cover the concrete surfaces, e.g., of the concrete dam with a natural turf sheet. However, appropriate method and technique for the above have not been proposed.
In addition to the foregoing, the following problem actually arises when one intends to lay turfs or the like.
In many large-scale facilities such as indoor sport facilities, gymnasiums and other multipurpose holes, an artificial turf is laid and removed depending on contents of the games and events. In this case, a problem actually arises in connection with storage of huge artificial turfs, which are to be laid in large-scale facilities. For example, if a warehouse for storing the artificial turfs cannot be ensured in the large-scale facilities, the warehouse must be independently prepared for storing them. If the independent warehouse is remote from the large-scale facilities, a time-consuming work is required for transferring the artificial turfs between the warehouse and the large-scale facilities. Further, the artificial turf is worn in accordance with use, and is considerably damaged when it is used for hard sport games such as a soccer. Therefore, the artificial turf requires a time-consuming repair.
Accordingly, a first object of the invention is to provide a plant growth sheet structure of a first type for growing a plant such as a turf which has the following advantages.
(1-1) Without changing a size or after cutting the structure into an appropriate size, the structure can be simply and easily laid in grounds such as a general house garden, a park, a river bank, a golf course, a hillock washed with rainwater and a seaside exposed to a strong wind as well as planting zones of various kinds of buildings, roads or the like, sport facilities and others. Also, it is possible to sow seeds of turfs, grasses and flowers, and grow them in the structure. Also, the structure can be moved to and from the above places.
(1-2) Sowed seeds, sprouts growing therefrom and others are suppressed from being moved and flowed out by the wind, rain, irrigated water or the like, which facilitates growth and maintenance of the plants.
(1-3) The whole structure is integral and has a sufficient resistance against decomposition. Sowed seeds as well as sprouts, roots and others are protected against a downward load, a lateral pulling force or the like, which also facilitates maintenance of growing and grown plants.
(1-4) It is possible to suppress an unpreferable appearance before growing of plants and even in such a case that grown plants are damaged or lost due to shaving or withering.
(1-5) The structure can be laid over possible seeds of weeds to restrict growth thereof, which also facilitates maintenance of growing and grown plants.
(1-6) A weight can be controlled, and thus its weight can be reduced to allow easy transfer. Also, the weight can be increased to improve stability of the laid structure at an installation place. The stability of the laid structure can be improved to allow use in sport facilities for some kinds of sports.
(1-7) The structure can be produced in an elongated form.
A second object of the invention is to provide a plant growth sheet structure of a second type, which holds seeds of plant such as turf seeds in advance, and has the following advantages.
The "turf seeds" mean the seeds of turf themselves as well as runners or the like which are obtained from cut turfs or the like, and from which a turf can be obtained.
(2-1) Without changing the size, or after cutting the structure into an appropriate size, the structure can be easily laid in grounds such as a general house garden, a river bank, a park, a golf course, a hillock washed with rainwater, and a seaside exposed to a strong wind as well as planting zones of various buildings, roads or the like, sport facilities and others. It is possible to grow plants from seeds of turf, grass or flower which are held in advance at the structure. Also, the structure can be moved to and from the above places.
(2-2) The plant seeds held at the structure, sprouts growing therefrom and others are suppressed from being moved or flowed out by the wind, rain, irrigated water or the like, which facilitates growth and maintenance of plants.
(2-3) The whole structure is integral and has a sufficient resistance against decomposition. Held seeds as well as sprouts, roots and others are protected against a downward load, a lateral pulling force or the like, which also facilitates maintenance of growing and grown plants.
(2-4) The structure also has advantages similar to those already described at the items (1-4) through (1-7) of the plant growth sheet structure of the first type.
A third object of the invention is to provide a natural turf sheet structure having the following advantages.
(3-1) Without changing the size, or after cutting the structure into an appropriate size, the structure can be easily laid in grounds such as a general house garden, a park, a river bank, a golf course, a hillock and a seaside as well as planting zones of various buildings, roads or the like, sport facilities and others. Also, the structure can be easily moved to and from the above places.
(3-2) The turf is suppressed from being moved or flowed out by the wind, rain, irrigated water or the like, which facilitates growth and maintenance of turfs.
(3-3) The whole structure is integral and has a sufficient resistance against decomposition. Sprouts, roots and others of the turf are protected against a downward load, a lateral pulling force or the like. Therefore, the structure can be used in the sport facilities. This also facilitates maintenance of the turf.
(3-4) As compared with a conventional natural turf sheet structure, it is possible to suppress an unpreferable appearance in such a case that turfs are damaged or lost due to shaving or withering.
(3-5) The structure can be laid over possible seeds of weeds to restrict growth thereof, which also facilitates maintenance of turfs.
(3-6) A weight can be controlled, and thus its weight can be reduced to allow easy transfer. Also, the weight can be increased to improve stability of the laid structure at an installation place. The stability of the laid structure can be improved to allow use in sport facilities for some kinds of sports.
(3-7) The structure can be produced in an elongated form.
A fourth object of the invention is to provide a method of growing a turf, in which a turf is grown at a concrete surface of a concrete dam, a retention pond or the like for covering the concrete surface with a natural turf so as to protect the surface against the direct sunshine, wind and rain, and to improve an appearance thereof.
A fifth object of the invention is to provide a method of laying a turf sheet structure, and in particular to a method of laying a turf sheet structure in large-scale facilities, by which it is possible to perform storage of the turf sheet structure before and after intended arrangement of the same, laying of the stored structure for the intended arrangement, and restoring and rearranging of the damaged turf sheet structure in a more simple and economical manner than a conventional artificial turf.